Here are some links I got from a friend who teaches Japanese in America. I haven't gone through them all yet. They're links to more links, so there's a lot of stuff there:
http://www.studystack.com/Japanese
http://www.sabotenweb.com/bookmarks/language.html#reference
http://www.tufs.ac.jp/st/personal/99/kawatsu/gahoh/index.html
http://www.sp.cis.iwate-u.ac.jp/icampus/u/linksj.jsp
http://www.nihongomemo.com/sharing.htm#You

エバン先生 13th

This is my recommendation of website. It would be useful for you and studetns when you browse Japanese websites. It automatically adds フリガナ above Kanji. (How clever!!)
http://www.hiragana.jp/en/

じゃあまたね^^
あき 13,sep

To get things started, I thought I'd also share some sites I used while in Japan. They're designed for teaching English, but many of the ideas can be adapted for teaching any language. So, here goes:

http://www.mes-english.com
(This has a lot of print outs available, and a few good game ideas)
http://jhsenglipediaproject.com/default.aspx
(A friend in Japan started this site, and it's really taken off. He's a great teacher with a lot of great ideas. The activities vary in quality, though, because most of them are all ideas and submissions from other teachers.)
http://www.eslcafe.com/ideas/
(There's a huge amount of game ideas here, too.)